RAM Mount Composite Surface Mount w/6.25" x 2" Top Plate [RAP-111U]The RAP 111U consists of a 2" x 1. 7" 2" x 1. 7" square base that contains the universal AMPs hole pattern, STANDARD LENGTH double socket arm and 6. 25" x 2" rectangle base. The rectangle base contains different combinations of pre drilled holes which will match up to many electronic devices and mounts, including Marine GPS, CB Radios, Ham Radios, Gimbal Brackets and more. The RAP 111U is Compatible With: Garmin Fishfinders and GPS Chartplotters